Model Plugin does not load

run a world with a world plugin -> world plugin creates a model (also with plugin).
If I create a sensor with a sensor plugin (dynamically with the world plugin) then the sensor plugin is loaded. The model plugin is not...

I tried multiple versions of gazebo (1.4, 1.6, 1.9). Can you give me a hint?

Comments

First very embarrassing error: I forgot to set the plugin path for the model plugin lib... but this is not the solution.... I will upload some more code and the output (there are no error / warning msg -> its just not loaded)

Second error: after the _parent->InsertModelSDF(sphereSDF); in the load method of the world-plugin there was a " node->WaitForConnection();" that waited for a message from the model plugin.... very stupid errors... sorry